Enhancing Voltage and Power Output Through the Structural Optimization of Coil–Magnet Transducers in Electromagnetic Vibration Energy Harvesters †

Electromagnetic vibration energy harvesters (EVEHs) have emerged as a promising approach to powering small electronic devices and sensors, particularly in remote or inaccessible locations where traditional power sources are impractical. This study investigates approaches for structurally scaling and optimizing the EVEH transducer magnet structure to maximize the magnet flux density, total flux density, harvested voltages and power output. Six design configurations have been analyzed in different coils and transducer magnet/flux guiding steel geometries. While the coil varies by using bulk or split coils, the magnet/flux guiding steel is varied by using different sizes. Analytical validation and simulations showed that these variations generally affected the transducer flux density per unit magnet volume (Formula presented.) and total volume (Formula presented.). Validation shows that configurations with a split center magnet with the smallest transducer volume attains preferable (Formula presented.) and power density by approximately 21.66%, 15.77% and 54.47% over the reference model without center magnet/steel. Therefore, the most structurally optimized configuration attained a light weight but a higher energy conversion/flux coupling efficiency. Also, the analysis showed that using split slotted coils is more efficient for energy harvesting than using bulk equivalent (single) coils counterparts. This is because the split coil will encourage more flux coupling than bulk coil. Additionally, the optimal load capacity is considerably reduced by approximately 50.00% on configurations with split coil. Therefore, split and bulk are respectively suitable for low- and high-impedance matching.